Motor control is the processing of controlling a position and velocity of a motor according to a position command and a speed command. For such motor control, various kinds of control methods have been proposed to achieve performance improvement.
On the other hand, the motor-driving apparatus is needed, in addition to such motor control, to perform connection to external devices or the like. For instance, in the case where a motor-driving apparatus is connected to external devices with a network, an amount of data to be processed is enlarged as speed of the network is increased in recent years. In addition to this, the motor-driving apparatus is necessary to deal with complicated operation commands. Accordingly, a network part of the motor-driving apparatus is required to perform significantly increasing processes. Further, various types of networks are available in a market. Thus, motor manufacturers are needed to adapt their network part to a plurality of networks depending on customer's requirements. However, if the motor manufacturers develop the network part individually, an enormous amount of man-hours will be necessary disadvantageously. Further, if entrusting external experts with the task of developing the network part, motor manufacturers each are necessary to disclose the entire control part, which is a mass of their know-how, to the external experts. This makes it disadvantageously difficult to entrust external experts.
Therefore, a technique for adapting to a network efficiently has been proposed.
For instance, a CPU board for connection to a host controller is separately provided in a motor-driving apparatus to perform analysis processing of serial communication data. To control a motor, data is transmitted and received between the CPU board and a servo board for performing motor control in another communication form. By doing so, even if a type of network connected to the controller is changed, it is only necessary to modify processing of the CPU board for connection to the host controller. Furthermore, the corresponding man-hours can be reduced significantly because there is little influence on a motor control part. Alternatively, even if entrusting external experts, motor manufacturers are not necessary to disclose motor control processing, so that the development can be entrusted in low-risk (e.g., see Patent Document 1).
For this application, with respect to a standard motor-driving apparatus, an externally attachable product is available in a market as an external option board. If a model is prepared to adapt the external option board to various types of networks, only replacement of the external option board makes it possible to adapt to various types of networks. Further, the motor control part and the network part are completely separated. Therefore, motor manufacturers are allowed to entrust external experts with the task of developing a motor-driving apparatus adaptable to various types of networks without disclosing their know-how in associated with motor control.
However, the conventional technique, described above, requires additional hardware such as a dedicated CPU board or an option board, which causes disadvantages such as a large size and a high cost.